It is common practice to transport large multiton freight containers overland on the bed areas of large trailers. The containers are often loaded onto the trailers and later removed from the trailers by large cranes. These cranes somewhat resemble large tunnel mechanisms having hoists suspended from their upper structural areas; the tractor-trailer unit is driven into the tunnel-like crane mechanism for loading and unloading the freight containers by the overhead hoists.
In certain circumstances, for example under battle field conditions, the large loader-unloader cranes may not be available at the field sites where it is desired to load or unload the freight containers. The present invention contemplates a trailer structure having built-in hoists for loading and unloading the freight containers. The principle aim of the invention is to provide a loader-unloader mechanism which can handle very large container weights in the neighborhood of twenty tons without toppling over.